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United States Patent |
5,268,560
|
Ueda
|
December 7, 1993
|
Key device
Abstract
A key device includes a plurality of coils arranged on a printed board
having an insertion hole along the longitudinal direction of the insertion
hole. One of the plurality of coils is an electromagnetic induction
generating coil connected to a power supply, and at least two of the
remaining coils are key signal generating coils. In a key main body which
can be inserted/removed into/from the insertion hole, a closed circuit is
formed on a printed board. In the closed circuit, a plurality of coils and
capacitors arranged between the plurality of coils are formed at positions
opposite to the plurality of coils arranged along the longitudinal
direction of the insertion hole. A bypass is formed in each of the coils
arranged in the key main body, and a coil or coils for specifying a key
type by switching operations of jumper line switching sections are
selected. A key signal or key signals are generated from a key signal
generating coil or key signal generating coils opposite to the selected
coil or coils.
Inventors:
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Ueda; Hiroyuki (Numazu, JP)
|
Assignee:
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Tokyo Electric Co., Ltd. (Tokyo, JP)
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Appl. No.:
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882456 |
Filed:
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May 12, 1992 |
Foreign Application Priority Data
Current U.S. Class: |
235/375; 235/492 |
Intern'l Class: |
G06F 015/20 |
Field of Search: |
235/375,492
361/171
|
References Cited
U.S. Patent Documents
2347072 | Oct., 1967 | Ross.
| |
4788623 | Nov., 1988 | Haug.
| |
Foreign Patent Documents |
0115747 | Aug., 1984 | EP.
| |
3244566 | Jun., 1984 | DE.
| |
0214410 | Mar., 1987 | DE.
| |
53-131733 | Nov., 1978 | JP.
| |
54-62753 | May., 1979 | JP.
| |
62-73513 | Apr., 1987 | JP.
| |
2079842 | Jan., 1982 | GB.
| |
Primary Examiner: Pitts; Harold
Attorney, Agent or Firm: Frishauf, Holtz, Goodman & Woodward
Claims
What is claimed is:
1. A key device comprising:
a printed board having an insertion hole;
key signal generating means including a plurality of coils arranged on said
printed board along a longitudinal direction of said insertion hole, said
key generating means comprising a power supply, an electromagnetic
induction generating coil connected to said power supply, and at least two
key signal generating coils;
a key main body comprising a printed board which can be inserter/removed
into/from said insertion hole, said key main body comprising a closed
circuit including a plurality of coils which are respectively arranged at
positions opposite to said plurality of coils of said key signal
generating means when said key main body is normally inserted into said
insertion hole, and jumper lines for selecting said coils to specify a key
type, said jumper lines being connected in series between said plurality
of coils through a capacitor such that said jumper lines can be switched
to a bypass; and
detecting means, connected to said key signal generating coils of said key
signal generating means, for detecting a key signal which is generated by
a key signal generating coil opposite to said selected coil of said closed
circuit when said key main body is normally inserted into said insertion
hole.
2. A device according to claim 1, wherein said plurality of coils of said
key signal generating means and said plurality of coils arranged on said
key main body comprise coil windings.
3. A device according to claim 1, wherein said plurality of coils of said
key signal generating means and said plurality of coils arranged on said
key main body comprise coil patterns formed on said printed board.
Description
BACKGROUND OF THE INVENTION
1. Field of the Invention
The present invention relates to electric equipments such as an electronic
cash register or to a key device used for a traveling bag.
2. Description of the Related Art
A cashier having a cashier code assigned to an electronic cash register,
for example, can be registered in this cash register and can operate it. A
keyboard is used as an input means for inputting the cashier code. There
are two methods of inputting a cashier code. First, after an input of a
cashier code is declared by a declarative key, the code is entered by
numerical keys (this method may be reversible), and second, a preset key
in which a cashier code is preset is used. In the first method, a cashier
code input is cumbersome, and if an erroneous code is input and has
already been registered, the input code is valid, and an erroneous
operation is performed. On the other hand, although the second method has
good operability, since the number of preset keys is limited, the number
of cashier codes which can be preset is very small. Therefore, in recent
years, an electronic cash register using an electromagnetic key switch as
a means for inputting a cashier code has been used.
FIG. 1 is a view showing an arrangement of a main part of a conventional
electromagnetic key switch of this type, as is disclosed in Published
Unexamined Japanese Patent Application No. 62-73513. In FIG. 1, a key 1
comprises a plate-like key main body 1a consisting of a magnetically
permeable material and a head portion 1b integrally formed at one end of
the key main body 1a. Reference numeral 2 denotes a key insertion hole in
which the key main body 1a is inserted. Four Hall elements 3a, 3b, 3c, and
3d are linearly arranged along the insertion direction of the key main
body 1a on a plate member 6 constituting the side portion of the key
insertion hole 2.
Magnet buried portions 4a, 4b, 4c, and 4d are formed in the key main body
1a such that the portions 4a, 4b, 4c, and 4d are arranged at positions
respectively opposite to the Hall elements 3a to 3d when the key main body
1a is normally inserted into the key insertion hole 2. Magnets 5 are
selectively buried in the magnet buried portions 4a to 4d.
The magnets 5 are buried in the magnet buried portions 4a and 4d of the
magnet buried portions 4a to 4d but not buried in the magnet buried
portions 4b and 4c. In this case, output signals a and b from the elements
3a and 3d of the Hall elements 3a to 3d are turned on by the magnetic
forces of the magnets 5, and output signals b and c from the elements 3b
and 3c are kept set in an OFF state.
As shown in FIG. 2, the output signals a, b, and c from the Hall elements
3a, 3b, and 3c are input to input terminal A0, Al, and A2 of a buffer IC
6, respectively, and the output signal d from the Hall element 3d is input
to a power supply terminal Vcc of the buffer IC 6. Output terminals YO,
Y1, and Y2 respectively corresponding to the input terminals A0, Al, and
A2 of the buffer IC 6 are connected to a microprocessor I/O port 7
constituting the control main body of the electronic cash register. That
is, the output signal d from the Hall element 3d serves as a drive power
supply of the buffer IC 6, and the output signals a to c from the Hall
elements 3a to 3c are fetched by the buffer IC 6 in response to an ON
state of the output signal d from the Hall element 3d, such that the
output signals a to c are loaded in a microprocessor (not shown) of the
electronic cash register through the I/O port 7.
In all keys, the magnets 5 are always buried in the corresponding magnet
buried portions 4d located at positions opposite to the Hall elements 3d
in the key main bodies 1a, and the magnets 5 are selectively buried in the
magnet buried portions 4a to 4c, thereby setting different types of keys.
For this reason, every time when different types of keys are required
according to different application purposes, the step of burying magnets
in pre-selected buried portions must be performed. Therefore, different
types of keys cannot be easily manufactured. In addition, since an
electromagnet is used, a low-profile key cannot be easily obtained.
SUMMARY OF THE INVENTION
It is an object of the present invention to provide a key device capable of
eliminating the above conventional drawbacks, forming different types of
keys in a simple process without burying magnets in a key main body, and
obtaining a low-profile key main body.
In order to achieve the above object, according to the present invention,
there is provided a key device comprising: a printed board having an
insertion hole; key signal generating means including a plurality of coils
arranged on the printed board along a longitudinal direction of the
insertion hole, the key generating means comprising a power supply, an
electromagnetic induction generating coil connected to the power supply,
and at least two key signal generating coils; a key main body comprising a
printed board which can be inserted/removed into/from the insertion hole,
the key main body comprising a closed circuit including a plurality of
coils which are respectively arranged at positions opposite to the
plurality of coils of the key signal generating means when the key main
body is normally inserted into the insertion hole, and jumper lines for
selecting the coils to specify a key type, the jumper lines being
connected in series between the plurality of coils through a capacitor
such that the jumper lines can be switched to a bypass; and detecting
means, connected to the key signal generating coils of the key signal
generating means, for detecting a key signal which is generated by a key
signal generating coil opposite to the selected coil of the closed circuit
when the key main body is normally inserted into the insertion hole.
According to the present invention with the above arrangement, there is
provided a key device in which different types of keys can be easily
formed by punching coil windings or patterned coils without burying
magnets in a key main body and the key main body can be thinned.
Additional objects and advantages of the invention will be set forth in the
description which follows, and in part will be obvious from the
description, or may be learned by practice of the invention. The objects
and advantages of the invention may be realized and obtained by means of
the instrumentalities and combinations particularly pointed out in the
appended claims.
BRIEF DESCRIPTION OF THE DRAWINGS
The accompanying drawings, which are incorporated in and constitute a part
of the specification, illustrate presently preferred embodiments of the
invention and, together with the general description given above and the
detailed description of the preferred embodiments given below, serve to
explain the principles of the invention.
FIG. 1 is a view showing an arrangement of a main part of a conventional
key device using an electromagnet;
FIG. 2 is a circuit diagram showing a conventional processing circuit of a
key signal;
FIG. 3 is a view showing an arrangement of a main body of a key device
according to an embodiment of the present invention in detail;
FIG. 4 is a view showing another embodiment of the present invention
wherein patterned coils are arranged in place of coil windings on a key
main body;
FIG. 5 is an enlarged view showing one of the coil windings arranged on the
key main body in the embodiment shown in FIG. 3;
FIG. 6 is a view showing an operation of the key device in the embodiment
shown in FIG. 3; and
FIG. 7 is a view showing another operation of the key device in the
embodiment shown in FIG. 3.
DETAILED DESCRIPTION OF THE PREFERRED EMBODIMENTS
An embodiment of the present invention will be described below with
reference to accompanying drawings.
FIG. 3 is a view showing an arrangement of a main part of a key device
according to this embodiment. Reference numeral 11 denotes a key main
body, and reference numeral 12 denotes a key insertion hole in which the
key main body 11 arranged on a printed board 15 is inserted. Four coils
L1, L2, L3, and L4 are arranged on the printed board 15 along the
longitudinal direction of the key insertion hole 12. A DC power supply E
is connected to only the coil L4 located at a position opposite to the
deepest part of the hole 12, and capacitors C1, C2, and C3 are connected
in series with the coils L1, L2, and L3 in the insertion hole,
respectively.
A key signal detection circuit 13 detects a signal a generated across the
coil L1, a signal b generated across the coil L2, and a signal c generated
across the coil L3. A signal detected by the key signal detection circuit
13 is loaded in a microprocessor constituting a control main body of a
electric equipment.
The key main body 11 is obtained by shielding a printed board 11a with a
shield member. On this printed board 11a of the key main body, a closed
circuit R is formed. In this closed circuit R, when the key main body 11
is normally inserted into the key insertion hole 12 as shown in FIG. 3, a
first coil L4a and a capacitor C4a are located at a position opposite to
the coil L4 connected to the power supply E, and three coils L1a, L2a, and
L3a are located at positions opposite to the coils L1, L2, and L3,
respectively. The coils L1a, L2a, and L3a are connected in series with
capacitors C1a, C2a and C3a, respectively.
The capacitors C1a to C4a and the coils L1a to L4a are alternately
connected in series on the key main body 11. The series circuit of the
coil L1a and the capacitor C1a, the series circuit of the coil L2a and the
capacitor C2a, and the series circuit of the coil L3a and the capacitor
C3a are connected to bypasses, respectively. Any one of the paths on the
coil side and the bypass side is selected by using jumper lines switching
sections J1, J2, and J3, thereby forming the closed circuit R.
In the embodiment shown in FIG. 3, coil windings are used in the coils L1
to L4 and L1a to L4a. However, as shown in FIG. 4, coil patterns L1b, L2b,
L3b, and L4b and capacitors C1b, C2b, and C3b may be alternately connected
to each other in series on a printed board 11a to form a circuit. In the
arrangement shown in FIG. 3, a switching operation of each of the jumper
line switching sections J1 to J3 is performed as follows. As shown in FIG.
5, for example, a jumper line 14 is selectively connected to the coil-side
terminal or bypass-side terminal of the coil L3 from the rear side of the
printed board, thereby performing a switching operation.
That is, as shown in FIG. 5, when the jumper line 14 is connected across
coil terminals P2 and P3, it is means that the coil L1a is selected in the
closed circuit R. When the bypass-side terminal is to be selected, the
jumper line 14 is connected across the terminals P1 and P3.
In the embodiment arranged as described above, when the key main body 11 is
normally inserted into an insertion hole 12, the coils L1 to L4 are
opposite to the coils L1a to L4a arranged on the key main body,
respectively. For this reason, since a current flows into the coil L4
located at a position opposite to the deepest part of the insertion hole
12 due to the operation of the power supply E, electromagnetic induction
occurs between the coil L4 and the coil L4a opposite to each other to
generate an induced current in the closed circuit R. As a result, the
current flows into the coils L1a to L3a in which the coil-side paths are
selected by the jumper line switching sections J1 to J3, and
electromagnetic induction occurs between the coils L1a to L3a and the
coils L1 to L3 opposite to each other, thereby outputting key signals a to
c from the corresponding coils L1 to L3. The key signals a to c output as
described above are detected by the key signal detection circuit 13 and
loaded in the microprocessor.
In the step of inserting the key main body 11, since an induced current
cannot be generated in the closed circuit R, no signal is generated by the
coils L1 to L3.
In FIG. 3, the coil-side paths are selected by the jumper line switching
sections J1, J2, and J3 in the coils L1a to L3a arranged on the key main
body 11. For this reason, when the key main body 11 is normally inserted
in the insertion hole 12, the signals a to c are generated by the coils L1
to L3, and this state (all the signals a to c are set in an ON state) is
detected by the key signal detection circuit 13 as a key signal.
In the embodiment shown in FIG. 6, the coil-side path is selected by the
jumper line switching section J2 in only the coil L2a on the key main body
11, and the bypass-side paths are selected by the jumper line switching
sections J1 and J3 in the coils L1a and L3a. Therefore, when the key main
body 11 is normally inserted into the insertion hole 12, the signal b is
generated by only the coil L2 opposite to the coil L2a, and this state
(the signal b is set in an ON state, and the signals a and c are set in an
OFF state) is detected by the key signal detection circuit 13 as a key
signal.
In the embodiment in FIG. 7, the bypass-side path is selected by the jumper
line switching section J2 in only the coil L2a, and the coil-side paths
are selected by the jumper line switching sections J1 and J3 in the coils
L1a and L3a. Therefore, when the key main body 11 is normally inserted
into the insertion hole 12, signals are generated by the coils L1 and L3
opposite to the coils L1a and L3a, respectively, and this state (the
signals a and c are set in an ON state, and the signal b is set in an OFF
state) by the key signal detection circuit 13 as a key signal.
As described above, according to the above embodiment, the key main body 11
is formed by the printed board 11, the four coils L1a to L4a are formed on
the printed board as coil patterns, and these coil patterns are connected
to each other in series through the capacitors C1a to C4a to form the
closed circuit R. Bypasses are arranged for the coils L1a to L3a, a coil
side-path and a bypass-side path can be selected by the jumper lines 14 in
each of the coils L1a to L3a, thereby forming the key main body 11.
Therefore, the key main body 11 can be easily processed compared with the
conventional case wherein a plurality of magnets are buried in a
plate-like key main body consisting of a magnetically permeable material.
In addition, the key main body of this embodiment can be thinned.
Furthermore, since a magnet is buried in a conventional key main body, the
type of the resultant key cannot be easily changed. However, in this
embodiment, types of key can be variably set by only switching the jumper
lines 14. For this reason, the present invention can advantageously cope
with a change in key type.
In the above embodiments, the four coils are arranged on the key main body
11, and the four coils are used for generating key signals. However, the
present invention is not limited to the embodiments. In addition, the
power supply E is connected to a coil located at the position opposite to
the deepest part of the hole 12. However, if a means for detecting that
the key main body 11 is normally inserted in the insertion hole 12 is also
arranged, a coil connected to the power supply is not limited to the
deepest coil.
It should be understood that various changes and modifications may be
effected without departing form the spirit and scope of the invention.
Additional advantages and modifications will readily occur to those skilled
in the art. Therefore, the invention in its broader aspects is not limited
to the specific details, and representative devices shown and described
herein. Accordingly, various modifications may be made without departing
from the spirit or scope of the general inventive concept as defined by
the appended claims and their equivalents.
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